Interlocked fastening device particularly applicable to electrical apparatus



, Nov. 4 1924.

4 1,514,378 H. J. FISHER ET AL INTERLOCKED FAS IENING DEVICEPARTICULARLY APPLICABLE TO ELECTRICAL APPARATUS Filed April 14, 1924Patented Nov. 4, 1924.

HAaRY Joslirnrismanyor PHILA ELPHIA, AND JAMEs Mm-REY, OF EAST ENGLAND,AssIGno s To A. xn xnoulea OOMFANYIIMITED, crew-imam- TYNE," DURHAM,ENGLAND, 'A BRITISH 'COMZPANY.

INTERLOCKED TASTENI'NG DIivi cE r n-Trq LARLY 'A'PPLICAB'LA'PPA'R'ATTIS.

'lpgilica'tion fi'le'a April 14, 1924. Serial No. 76.1587.

To all whom it may comm; I

Be it' known that "fwe, HARRY JosriPH FISHE and James MI'RREY, subjects'ofjthe King of England, and'residing; respectively, 6 at Philadelphia,in thec'oun'ty of Durham, England, and East Boldon, in' 'the county 'ofDurham, England, have invented certain new and useful Improvementsinlfnterlocked Fastening Devices Pai'ticulaifly Applicable to ElectricalApparatus, of which the following is a specification. v r

This invention relates to a fastening device for securing twomembersitogeth er of the type in which the device is interlocked withsome Other'niechaniSI n in such an anner that the two members cannot becau 'sed to'engage with one another'on'to disengage except when theother "iii'echa nism" is"'in some definite position. K t

The invention is more particularlyapplicable to electrical'apparatus,alndis p'riihztrily designed with the object ofl'pi oviding' anelectrical plug and socket connection;"whrein the plug can only be,inserted in'the socket 'anism has been operated andban'not beiwithdrawn'from the socket until after the switch or other mechanism hasbeen'ret'urned to its initial position. 7 v

The fastening "device according' fto the present invention "comprises abolt-"o1' rod pivoted to one of the twohneinbers itofbe securedtogether, and afdrum"or'sleeve movable longitudinally there-on, Apartthe drum or a projection' thereon isso shaped as tolie in or outof'thepath of "an interlockingirodaccordingto the position of the drumon the bolt. heidru'rn' is caused to move alon 'thebolt inea-nsof arotatable head or the like, wh1ch"'al'soengages "with e Qft wo members.n smh as "to these inehib'ers together in e'efiga hgP o 1 a V The"rotatable head may-hav two flanges :iiisiiitied to eng ge respectivelwith the, two sides of a fslotted lugfon thefsecond ineniber sofas f ti)assist the engagement or separation f h 't l i b'e -v T e d ii n s h fagain t idt'ation relative to the bolt and 'c'on= v'eiiientlyfits"projection "lies in the path of the interlocking r dije eepp when thetwo m m fi fimv' th' rt he. Wtdble head is preferably ftirfii'ed with athread onjthe drum, between the druni and a'colla ij as to tendtovariety; of purposes,

before a controllingswitchbrother "Inechv in such a manner drum lntoaposition in lies in the path of the int he invention may 111 variousways and drawings illustrate by preferred arrangement" trical plug andSocket 0 ticularly intendedfor. us

places where it is of prevent the occurrence. of a spar E To Thouscrew-thread engaging in a spr ng'fbeing provide? 1 fthebo niovelthewhich its projection zl i f tgr d-n .t ,1 be carriedinto practlce' maybe ailel sdfftl l c'mml yins em a a 'rli 'd t9 ankl i et pn I J' PQrPQral i sand. he r at m er nse to i b ase ing that the controlling ls witch returned to the off-position before thef plugv is inserted in orwithdrawn from the'so'cket. In

these drawings,

' Figure 1 shows the lpkie gb in horizontal section in the closedposition, I

j Figure 2is a plan ofthe bolt in the open position, and

winged nuts which on the plug'C, position in the gure 3 is asideelevation ofthe bolt,

e socket A has pivpu fn 's st #1 h 1 re ammg rawings) carry soas toclainp the socket A, These nuts each carry two flanges which engage withone side or the other oftheocorresponding, lug and thus assist inwithdrawing the a plug from thesocket or in inserti U The bolt B, otedat B surrounded n it therein. 1

used fo1 t1e interlock is .pivto lugs A on the socketand is by a drum.Dwvhich is free, .to

move longitudinally on the bolt but is keyed or slotted as at D,

of a slotted lug'C vided for this bolt threadfin the drum 1).

vided between the drum fi 'p the jb f B Lin tend to move the driim towaii 1 of the bolt, outer and, which preve r p f l silch a to prevent itfrom rotating relative to the bolt ll? ther ig; sipmins t i i i s E rambeing detached completely from the drum D. The end B of the bolt isarranged never to project beyond the head E so that the operators handis protected from damage.

The drum D has a lateral projection D which is moved into and out of thepath of an interlocking rod G as the head E is rotated. Thus when theplug C is clamped into the socket A, as shown in Figure 1, thisprojection 1) lies out of the path of the interlocking rod G, which istherefore free to move. Vhen, however, the head E is unscrewed towithdraw the plug C from the socket A, the drum D travels along the boltB and brings the projection D into the path of this red G.

The interlocking rod G may be connected to any desired mechanism suchfor example as a switch controlling the electrical circuit containingthe plug and socket. Thus when the plug is clamped in the socket and theprojection D is out of the path of the interlocking rod G, the switchmay be operated. hen the switch is turned into the on position, this rodG moves into the path of the rojection D and prevents the head E fromeing unscrewed far enough to withdraw the plug. In Figure 3 the rod G isshown in this position, whilst the off position of the end of the rod isindicated in chain line at G.

W'hen the plug G is clamped in the socket A, the outer flange E of thehead E is held tightly against the lug C on the plug by means of thespring F, this spring being made strong enough to prevent the plug frombeing withdrawn except by unscrewing the head E. When it is desired towithdraw the plug from the socket, the switch must be turned oil? toremove the interlocking rod G from the path of the projection D on thedrum D. The head E is then unscrewed and the drum I) moves down alongthe bolt B under the action of the spring F, the outer flange E' of thehead E still remaining in contact with the slotted lug C. After the drumD has reached the end of its travel and its projection D lies in thepath of the inter locking rod G, the head E begins to move as it isrotated until its inner flange E comes into contact with the other sideof the slotted lug C. The winged nuts on the other retaining bolts arealso unscrewed until their inner flanges engage with the lugs, andfurther rotation of the head and theiruts causes the plug to begin tomove out of the socket. The bolts are then swung out about their pivotsuntil the head and the nuts cease to engage with the slotted lugs andthe plug can be completely removed. This position is shown in Figure 2.Since the projection D on the drum D now lies in the path of theinterlocking rod G, it is impossible to operate the switch while theplug is out of the socket. No current can therefore be flowing throughthe circuit while the plu is being withdrawn from or inserted into t iesocket, and it is therefore impossible for a spark to occur. It is alsoimpossible for the terminals of the socket to be exposed when the switchis on and thus for anyone to receive a shock by touching the live socketterminals.

To clamp the plug into position in the socket, it is first of allinserted therein and the bolts are swung in until the nuts and the headare in engagement with the slotted lugs. Tightening up these membersthen forces the plug right home into the socket (this action beingassisted by the spring F) and clamps it into position. Further rotationof the head E moves the drum 1) along the bolt B until its projection Dis a ain out of the path of the interlocking ro G. The switch can now beoperated. and the plug cannot again be withdrawn until the switch is inthe off position.

i It will be understood that the construction described is given only byway of example and the details of construction may be varied withoutdeparting from the scope of the invention. Thus for example the head maymake a screw-threaded engagement with the bolt as well as with the drum,the necessary motion of the drum being caused owing to a difierencebetween the pitches of the two threads. Modifications may also be madeto suit the requirements of any particular purpose to which thefastening device according to the invention is applied.

What we claim as our invention and desire to secure by Letters Patentis 1. In a fastening device ad: ted to secure two members together andto interlocked with some other mechanism, the combination with the twomembers, of a bolt pivoted to one of the members, a rotatable headadapted to engage with the second member in such a manner as to clampthe two members together in the engaging position, a drum so connectedto the head and the bolt as to move longitudinally along the bolt whenthe head is rotated, and an interlocking rod operated by the mechanismwith which the fastening device is to be interlocked, the arrangementbeing such that a part of the drum lies in or out of the path of theinterlocking rod acgording to the position of the drum on the olt.

2. In a fastening device, the combination of the two members which areto be secured together by the device, a bolt pivoted to one of themembers, a slotted lug on the second member, a rotatable head having twoflanges adapted to engage respectively with the two sides of the slottedlug so as to assist in the engagement or separation of the two memberswhen the head is rotated a drum movable longitudinally on the bolt butheld against rotation relative thereto, means whereby the drum is causedto travel along the bolt when the head is rotated, an interlocking. rodoperated by some other mechanism with whichthe fastening device is to beinterlocked, and a projection on the drum which lies in the path of theinterlocking rod except when the two members are clamped together.

3. In a fastening device adapted to secure two members together and tobe interlocked with some other mechanism, the combination with the twomembers, of a bolt pivoted to one of the members, a rotatable headadapted to engage with the second member in such a manner as to clampthe two members together in the engaging position, a drum movablelongitudinally on the bolt but held against rotation relative thereto,the drum being provided with a screwthread engaging with a correspondingthread on the head whereby the drum is caused to travel along the bolt,when the head is rotated, an interlocking rod operated by the mechanismwith which the fastening device is to be interlocked, and a projectionon the drum which lies in the path of the interlocking rod exceptwhenthe two members are clamped together.

4;. In a fastening device, the combination of the two members which areto be secured together by the device, a bolt pivoted to one of themembers, a slotted lug on the second member, a rotatable head having twoflanges adapted to engage respectively with the two sides of the slottedlug so as to assist in the engagement or separation of the two memberswhen the head is rotated, a drum movable longitudinally on the bolt butheld against rotation relative thereto, the drum being provided with ascrewthread engaging with a corresponding thread on the head whereby thedrum is caused to travel along the bolt when the head is rotated, and aninterlocking rod operated by some other mechanism. with which thefastening device is to be interlocked, the arrangement being such that apart of the drum lies in or out of the path of the interlocking rodaccording to the position of the drum on the bolt.

5. In afastening device, the combination locking rod.

of the members, a slotted lug on the second member, a rotatable headhaving two flanges adapted to engage respectively with the two sides ofthe slotted lug so as to assist in the engagement or separation of thetwo members when the head is rotated, a drum movable longitudinally onthe bolt but held against rotation relative thereto, the drum beingprovided with a screwthread engaging with a corresponding thread on thehead whereby the drum is caused to travel along the bolt when the headis rotated, an interlocking rod operated by some other mechanism withwhich the fastening device is to be interlocked, a projection on thedrum which lies in the path of the interlocking rod except when the twomembers are clamped together, and a spring which tends to move the druminto a position in which its projection lies in the path of theintertion with the two members, of a bolt pivoted to one of the members,a rotatable head adapted to engage with the second member in such amanner as to clamp the two members together in the engaging position, adrum movable longitudinally on the bolt but held against rotationrelative thereto, the drum being provided with a screwthread engagingwith a corresponding thread on the head whereby the drum is caused totravel along with the bolt when the head is rotated, an interlocking rodoperated by the mechanism with which the fastening device is to beinterlocked, a projection on the drum its projection lies in the path ofthe interlocking rod according to the position of the drum on the bolt,and a spring which tends to move the drum into a position in which itsprojection lies in the path of the interlocking rod.

In testimony whereof we have signed our names to this specification.

HARRY JOSEPH FISHER. JAMES MIRREY.

